Variola : Sheeppox. 359 



the ear, an inch from the tip is usually selected, though there is 

 here an added element of danger, owing to its proximity to the 

 eye. The insertion is made with an ordinary suture needle, 

 which is introduced obliquely under the epidermis about one line, 

 and pressed upon with the thumb as it is withdrawn. A still 

 better instrument is the inoculation needle or lancet with a groove 

 or spoonlike hollow on one side. Or the skin may be scratched or 

 abraded with the lancet, as in vaccination, until serum oozes, 

 when the virus is rubbed on and the part is covered with a piece 

 of sticking plaster. On the third or fifth day the flock is again 

 examined and those that have failed to take are ovinated anew. 



The virus is most conveniently taken direct from the affected 

 sheep, but it may be preserved in capillary tubes, or on glass or 

 ivory points, or mixed with glycerine between glass plates, or 

 finally, the first scab well dried may be preserved and utilized, a 

 minute portion being inserted with the lancet in a pocket made 

 under the epidermis. 



Attempts have been made to secure a mitigated and safer virus, 

 by diluting the lymph with water or normal salt solution ( i : 50- 

 150) (Peuch), by amputating the seat of inoculation (the tip of 

 the ear) on the 4th or 7th day, when the vesicle is formed (Gal- 

 tier) , by taking a susceptible sheep and inoculating it with sheep- 

 pox virus for ten consecutive days, and then selecting for use the 

 lymph from the papule of the sixth inoculation. The inocula- 

 tions of the seventh day and later give rise to no papule even 

 (Pourquier). By this means it is claimed that the inoculated dis- 

 ease remains strictly local, passes through its successive .stages in 

 a shorter time (15 days or less), and is perfectly harmless to the 

 sheep inoculated. Nocard and Mollereau sought the same end 

 by mixing the virus with oxygenated water, and Semmer and 

 Raupach by heating it to 130° F. In view of the facts that it is 

 only under extraordinary conditions that ovination is permissible 

 at all, and that the mortality, resulting from it can be kept down 

 to about I per cent., it seems hardly worth while to attempt to 

 obviate this loss, by any method which may come short of the 

 full measure of immunity. 



Ovination confers immunity for a year or longer. 



The care of the flock during eruption is the same as in sheep- 

 pox contracted in the usual way. 



